717 research outputs found
Förslag till program för nationella provningsjämförelser av marin mjukbottenfauna
No full textI arbetet med denna rapport har ingått att ta del av närliggande länders eventuella program för provningsjämförelser. Det visade sig att inget av de nordiska länderna har ett fungerande program för provningsjämförelser av mjubottenlevande marin makrofauna. Av Östersjöländerna har endast Tyskland ett utvecklat och sedan år 2000 fungerande system. För västerhavets del har Storbrittanien ett välutvecklat system som fungerat i 15 år. Såväl det tyska som det brittiska systemet har studerats och bildat underlag för slutsatserna i denna rapport. Som underlag har även erfarenheterna från tidigare internationella interkalibreringar (Ankar 1976, Ankar m fl 1978, HELCOM 1991) och en tidigare nationell (Cederwall 2002) använts
Förslag till program för nationella provningsjämförelser av marin mjukbottenfauna [Elektronisk resurs]
No full textI arbetet med denna rapport har ingått att ta del av närliggande länders eventuella program för provningsjämförelser. Det visade sig att inget av de nordiska länderna har ett fungerande program för provningsjämförelser av mjubottenlevande marin makrofauna. Av Östersjöländerna har endast Tyskland ett utvecklat och sedan år 2000 fungerande system. För västerhavets del har Storbrittanien ett välutvecklat system som fungerat i 15 år. Såväl det tyska som det brittiska systemet har studerats och bildat underlag för slutsatserna i denna rapport. Som underlag har även erfarenheterna från tidigare internationella interkalibreringar (Ankar 1976, Ankar m fl 1978, HELCOM 1991) och en tidigare nationell (Cederwall 2002) använts.</p
S 7 and. . .
No full textWe investigate the seven-sphere as a group-like manifold and its extension to a Kac-Moodylike algebra. Covariance properties and tensorial composition of spinors under S 7 are defined. The relation to Malcev algebras is established. The consequences for octonionic projective spaces are examined. Current algebras are formulated and their anomalies are derived, and shown to be unique (even regarding numerical coefficients) up to redefinitions of the currents. Nilpotency of the BRST operator is consistent with one particular expression in the class of (field-dependent) anomalies. A Sugawara construction is given. published in Commun.Math.Phys. 167 (1995) 373. ? e-mail [email protected] y e-mail [email protected] M. Cederwall and C.R. Preitschopf, "S 7 and c S 7 " 1. Preliminaries. This paper is devoted to an investigation of the seven-sphere as a manifold equipped with group-like multiplication, and to its extension to a Kac-Moody-like algebra. As is well known, the seven-..
Introduction ti Division Algebras, . . .
No full textA very basic introduction is given to the roles of division algebras and the related sphere algebras concerning the structure of space-time in the dimensionalities D = 3; 4; 6 and 10, with special emphasis on twistors transformations for lightlikeness conditions and Hopf maps, together with some outlook for particle and string theory. Talk presented at the Theoretical Physics Network Meeting at NORDITA, Copenhagen, September 1993 ? e-mail [email protected] M. Cederwall, "Introduction to Division Algebras, Sphere Algebras and Twistors" This introduction, given the condition that it should fit into a single lecture, will be quite schematical. Many mathematical and technical details will be left out, for the purpose of giving a more intuitive overview of the subject. The intention is that the listener/reader should get a starting point for more detailed or extensive study. There will be nothing said about supersymmetry, although its incorporation in the context of twistors is very ..
World-volume fields and background coupling of branes
No full textthis paper, are by now fairly well understood. Although a fundamental microscopic formulation of the theory is still missing, the evidence is overwhelming that the different perturbative superstring theories, their low-energy supergravity theories and 11-dimensional supergravity are different manifestations of one underlying non-perturbative theory. In this talk, there is not much time to discuss the roles that the different elementary and solitonic objects have in the various duality transformations between different perturbative theories. We refer to ref. [1]. Some will be mentioned briefly, but the emphasis is put on the description of the dynamics of branes occurring in superstring theory/M-theory. 2. Charged branes The means to describe brane dynamics is to formulate actions, fulfilling certain requirements. In this section, some things will be said about the basic ingredients in these actions. The methods will later be refined. We let the dimensionality of the brane world-volume be p+1 and that of Martin Cederwall: "World-volume fields and background coupling of branes" : : : : : : : : : : : : : : : : 2 space-time D
An action for the super-5-brane in D=11 supergravity
No full text: An alternative path is taken for deriving an action for the supersymmetric 5brane in 11 dimensions. Selfduality does not follow from the action, but is consistent with the equations of motion for arbitrary supergravity backgrounds. The action involves a 2-form as well as a 5-form world-volume potential; inclusion of the latter makes the action, as well as the non-linear selfduality relation for the 3-form field strength, polynomial. The requirement of invariance under -transformations determines the form of the selfduality relation, as well as the action. The formulation is shown to be equivalent to earlier formulations of 5-brane dynamics. M. Cederwall, B.E.W. Nilsson, P. Sundell: "An action for the super-5-brane: : :" : : : : : : : : : : : : : : : 2 11-dimensional supergravity [1] is believed to be the low-energy effective theory for M-theory. Arising as a strong coupling limit of type IIA superstring theory [2], it is connected to the entire web of dualities relating different v..
Scalar soliton quantization with generic moduli
No full textThis article is distributed under the terms of the Creative Commons
Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in
any medium, provided the original author(s) and source are credArticle funded by SCOAP3. CP is
a Royal Society Research Fellow and partly supported by the U.S. Department of Energy
under grants DOE-SC0010008, DOE-ARRA-SC0003883 and DOE-DE-SC0007897. ABR
is supported by the Mitchell Family Foundation. We would like to thank the Mitchell
Institute at Texas A&M and the NHETC at Rutgers University respectively for hospitality
during the course of this work. We would also like to acknowledge the Aspen Center
for Physics and NSF grant 1066293 for a stimulating research environment which led to
questions addressed in this paper
Superembeddings, Non-linear Supersymmetry and 5-branes
No full textWe examine general properties of superembeddings, i.e., embeddings of supermanifolds into supermanifolds. The connection between an embedding procedure and the method of non-linearly realised supersymmetry is clarified, and we demonstrate how the latter arises as a special case of the former. As an illustration, the super-5-brane in 7 dimensions, containing a self-dual 3-form world-volume field strength, is formulated in both languages, and provides an example of a model where the embedding condition does not suffice to put the theory on-shell. T. Adawi, M. Cederwall, U. Gran, M. Holm, B.E.W. Nilsson: "Superembeddings: : :" : : : : : : : : : : : : : 2 1. Introduction Our understanding of string theory at the non-perturbative level has gone through a dramatic improvement in recent years. Some of the key aspects of this development are connected to the central role played by solitonic solutions of the low energy field equations, i.e., various brane configurations that solve the field e..
Prolonged mechanical ventilation in Swedish intensive care units: patient characteristics, prevalence, weaning and challenges in care
No full textThe overall aim of this thesis was to explore the care of adult patients on prolonged mechanical ventilation (PMV) in Swedish intensive care units (ICUs). Secondary aims were to identify the prevalence, characteristics and outcome in patients with PMV and the presence of person-centred care (PCC) during prolonged weaning in Swedish ICUs. Study I. Registry study identifying adult admissions to Swedish ICUs requiring mechanical ventilation ≥ 7 days. Admissions on PMV > 21 days constituted a small proportion of all admissions but occupied a significant part of ICU capacity. Use of ICU bed days and ICU mortality was lower compared to international studies. Study II. Survey of adult Swedish ICUs (n = 77) identifying care practices and protocols for adult patients undergoing mechanical ventilation > 7 days. Results showed low levels of weaning and mobilisation protocols, individualised approaches were preferred and interprofessional decisions were common. Few ICUs promoted primary nursing models or PCC approaches. Study III. Qualitative interview study exploring critical care nurses’ approach for management of patients during prolonged weaning from mechanical ventilation. Results showed that critical care nurses played a key role in prioritising, initiating and driving the weaning process. Study IV. Secondary analysis of qualitative interviews identifying the presence of PCC during prolonged weaning from mechanical ventilation. Results showed evidence of PCC undertaken during prolonged weaning, but also barriers such as a lack of team collaboration and staff resources. In conclusion, patients on PMV in Swedish ICUs comprised a relatively small proportion of ICU admissions but consumed a significant part of ICU capacity. Individualised approaches were preferred, and interprofessional collaboration was common. ICUs showed low level of care practices based on PCC, but PCC was present during prolonged weaning. Critical care nurses in the ICU played a key role in individualising care and increasing patient participation during prolonged weaning
M-branes on U-folds
No full textWe give a preliminary discussion of howthe addition of extra coordinates in M-theory, which together with theoriginal ones parametrise a U-fold, can serve as a tool forformulating brane dynamics with manifest U-duality. The redundantdegrees of freedom are removed by generalised self-duality constraintsor calibration conditions made possible by the algebraic structure ofU-duality
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